Danish Patent Application No. 1832/86 discloses an apparatus of the kind referred to. The apparatus according to Danish Patent Application No. 1832/86 is intended to be able to function even with deformed sticks. Experience has shown, however, that when using high rates of delivery of sticks, occurring in intermittent operation, high demands are placed on the construction of the carrier, in this case constituting a belt with pockets, into which the sticks are to be pressed singly from the stack of sticks. Thus, the sticks are to be pushed directly into the pockets under the action of a force applied through the stack. For this reason, this force will be continuously exerted against the belt, causing wear of the latter. As it is also necessary for the pockets formed in the belt to have a depth not exceeding the thickness of a stick in order to be able to destack one stick at a time, problems may arise in making the pockets hold sticks that are not quite straight.
Another example of the prior art is disclosed in U.S. Pat. No. 3,478,703, in which a belt is likewise used for destacking sticks singly from a stack under constant pressure, and in which use is also made of support plates at the part of the belt, in which the sticks are conveyed. In this example, the belt is adapted to run back and forth between the positions for receiving and delivering the sticks. Thus, even with this construction, there are problems related to the demands placed upon the construction of the belt and to the operating rates that may be achieved.
A general problem when using chains for destacking sticks is that these chains are subject to wear, causing particles to be transferred to the sticks and hence to the ice-cream bodies, especially when using chains of plastic material. For this reason it will be necessary to make the chains from wear-resisting material, typically stainless steel, in order to reduce the transfer of particles to a level compatible with the increasingly strict requirements relating to transfer of particles to foodstuffs, e.g. from the so-called HACCP directive coming into force in the European union in January 1996. There is, however, a drawback with using metal chains, in that the metal chains are complicated and costly to manufacture and also relatively heavy, thus reducing the operating rate that can be achieved.
Further, from DE-OS-1,601,078 it is known to single-out sticks from a number of sticks in a bin by using a chain conveying the sticks to an inserting device or a buffer store. When a buffer store is used, the sticks are periodically lifted up from the chains into the buffer store, in which the sticks are stacked by means of a wheel provided with teeth. In contrast: when the sticks are delivered from the buffer store, they will abut against the chain as in the above examples and be destacked into empty pockets on the chain by means of a pivoted rod and a stationary abutment co-operating with the pockets in the chain. For this purpose, the pockets are set at an angle. This arrangement results in a complicated construction with many moving parts, that are difficult to clean and with which it is difficult to achieve high operating rates.
A further example is disclosed in U.S. Pat. No. 1,953,506, in which the sticks are destacked using a piston rod pushing a stick out of the stack in the longitudinal direction of the stick, the latter being pushed out through an opening larger than the thickness of one stick but smaller than the thickness of two sticks. This construction requires a large abutment pressure from the stack, and also requires a strong force to eject the sticks in the longitudinal direction. At the same time, there is a risk of a stick getting jammed, which may happen when the piston rod, being thinner than the sticks, functions like a chisel and splinters the stick. Further, even this construction makes it difficult to achieve high operating rates.
Further, it is known from U.S. Pat. No. 4,105,384 (corresponding to Danish Patent Application No. 2884/75) to construct the destacking and carrier means as a sliding carriage running back and forth between the positions for receiving and delivering the sticks. In this example, the sliding carriage comprises pockets for the sticks having an oblique edge facing in the direction of forward movement and a mainly perpendicular edge facing opposite to the direction of forward movement. With this arrangement, the sticks are relatively easily placed in the pockets and lie loosely in the latter during the forward movement. When the sticks lie loosely in the pockets, there is a limit to how fast the sliding carriage with the sticks can be advanced and stopped, and time is also needed to return the carriage after having delivered the sticks.
Further, the tracks guiding the sliding carriage cause problems, as dirt may collect in them and disturb the operation, and if e.g. the dirt collects in the form of a layer in the guide track and lifts the sliding carriage, the sticks may be placed in positions offset from those desired. Still further, if the guides are twisted, e.g. caused by re-adjustment of the machine, e.g. when moving machine components, the movement of the sliding carriage may be changed and/or prevented, such as by jamming.
A further example of a method of destacking sticks may be seen in U.S. Pat. No. 4,323,336. In this example, the sticks are destacked singly by means of two oppositely placed helix wheels penetrating in between the sticks at the ends of the latter and conveying the sticks to a carrier belt and transferring them to the latter. With this method of destacking and conveying of sticks there is likewise a limit to the rates that may be achieved, and sticks that are skewed or deformed in some other way may cause problems.